Semiconductor device having a liquid cooling module

ABSTRACT

A semiconductor device comprises a mounting substrate, a semiconductor element provided above said mounting substrate, a package substrate provided above said mounting substrate with said semiconductor element therebetween and electrically connected to said semiconductor element via a primary connecting bump, a liquid cooling module cooling said semiconductor element by a liquid refrigerant, in which a heat receiving section of the liquid cooling module is disposed between said semiconductor element and said mounting substrate, and a plurality of secondary connecting bumps provided between said package substrate and said mounting substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device.

2. Description of the Related Art

Conventionally, in order to increase speed and capacity in asemiconductor package, there is an example of stacking a number ofmemory elements in layers in one package, an example of loading a memoryelement and a logic element together in one package, or the like.

For example, JP 2005-244143 describes a semiconductor device in which anumber of semiconductor memories are mounted on the top surface of aresin interposer (corresponding to a package substrate), and in which aninterface chip is stacked on its top layer with a through electrode witha short wiring distance.

Further, “Wide band/large-capacity-memory-loaded SMAFTI packagetechnique” (NEC Technical Journal vol. 59, No. 5/2006, pp. 46-49)describes a general-purpose LSI package in which a micro wiring body(corresponding to a package substrate) called an FTI (FeedthroughInterposer) is inserted between a logic chip and a large-capacity memorychip.

In a semiconductor package, in the case in which the heating value of asemiconductor element is higher than an allowable value, a radiator ismounted on the package in order to suppress a rise in the temperature ofthe semiconductor element. Therefore, a technique of reducing thethermal resistance between the radiator and the semiconductor element isrequired.

For example, JP 2005-244143 describes the configuration in which aninterface chip with a large heating value is mounted on the uppermostlayer near a radiator plate.

Further, JP 9-260554 describes a semiconductor package in which a heattransfer plate having high thermal conductivity is provided between theundersurface of a semiconductor element and a mounting substrate.

JP 9-293808 describes the configuration in which a metallic heat releasefin is mounted on the back surface of the semiconductor element exposedon the top surface of a package, via an adhesive.

Recently, a liquid-cooling method which makes noise reduction and highheat radiating performance compatible has been put to practical use. Forexample, FIG. 2 of “Water-cooling technique for hot devices, Aiming atpopularization by standardization and downsizing” (Nikkei Electronics,2003. 7.21, pp. 59-68) illustrates an example of practical use in whichheat is transported to the heat radiating section disposed at a distantposition from the heat receiving section disposed on a microprocessor. Awater-cooling module includes a heat receiving section (also called aheat absorbing section), a reservoir tank, a heat radiating section(also called a heat exchanger), a pump and a pipe connecting them, asmain components.

Further, there is an example of using a sheet, in order to downsize thecomponent of liquid cooling. For example, JP 2001-237582 describes theconfiguration in which a heat radiating section is formed into a bagshape by a flexible sheet having high heat resistance and high thermalconductivity. JP 2007-10277 describes the configuration in which a heatradiator and a heat absorber are formed by bags made of awater-resistant sheet.

As the best liquid-cooling method, there is an example of thedevelopment of a cooling module with high efficiency that uses a finemicro-channel of 200 μm or less. For example, FIG. 7 of “Water-coolingtechnique for hot devices, Aiming at popularization by standardizationand downsizing” illustrates a configuration in which amicro-channel/heat sink is mounted on the upper portion of themicroprocessor via grease. The micro-channel/heat sink is configured byforming a trench having a width of 150 μm or less and a depth of 200 μmin a thin plate of silicone by an MEMS technique.

Further, in a case of a package in which chips are stacked in layers,there is also an example of cooling individual chips in the package. Forexample, JP 2005-5529 describes the method for liquid-cooling the insideof a package by using a hollow portion formed by stacking semiconductorelements via bumps as a channel.

In order to obtain high speed transmission performance with a stackedmemory by a through electrode, the interface chip is desirably disposedin a lower layer instead of an upper layer of the stacked memory.Because, in the case in which the interface chip which controls signaldistribution is on the upper layer of the stacked memory, if the stackedmemory becomes thicker, the transmission path will become longer, andtherefore, a signal received from the solder ball, which is the inputand output terminal of the package, would be delayed.

As described in “Wide band/large-capacity-memory-loaded SMAFTI packagetechnique”, a logic chip on the undersurface of a package substrate isadvantageous with respect to signal transmission. However, when theheating value of the logic chip becomes large, space for mounting thefin described in JP 9-293808, and the water-cooling jacket illustratedin FIG. 2 of “Water-cooling technique for hot devices, Aiming atpopularization by standardization and downsizing” cannot be ensured.Meanwhile, as described in JP 9-260554, a heat transfer plate can beprovided in this space. However, the heat radiating ability of themounting substrate is too small to cool the logic element that has alarge heating value (of tens of watts).

Further, the periphery of a logic chip is surrounded by mounting bumps,and therefore, even if a thin cooling jacket comprising themicro-channel illustrated in FIG. 7 of “Water-cooling technique for hotdevices, Aiming at popularization by standardization and downsizing” ismounted, space for receiving a pipe cannot be provided. Meanwhile, theliquid-cooling method in which a refrigerant flows into a space betweenthe chips inside the package is likely to cause corrosion to the circuitsurface between the chips and to electrical connection portions of theupper and lower chips.

Accordingly, in a semiconductor device in which a mounting substrate,the semiconductor element and a package substrate are sequentiallystacked in layers, a technique for efficiently cooling a semiconductorelement is needed.

SUMMARY

In one embodiment, there is provided a semiconductor device thatcomprises a mounting substrate, a semiconductor element provided abovesaid mounting substrate, a package substrate provided above saidmounting substrate with said semiconductor element therebetween, andelectrically connected to said semiconductor element via a primaryconnecting bump, a liquid cooling module cooling said semiconductorelement by a liquid refrigerant, wherein a heat receiving section ofsaid liquid cooling module is disposed between said semiconductorelement and said mounting substrate, and a plurality of secondaryconnecting bumps provided between said package substrate and saidmounting substrate.

In another embodiment, there is provided a semiconductor device thatcomprises a mounting substrate, a first semiconductor element providedabove said mounting substrate, a package substrate provided above saidmounting substrate with said first semiconductor element therebetween,and electrically connected to said first semiconductor element via aprimary connecting bump, a second semiconductor element provided abovesaid first semiconductor element with said package substratetherebetween, and electrically connected to said first semiconductorelement via said primary connecting bump and a through electrodeprovided at said package substrate, a liquid cooling module cooling saidsemiconductor element by a liquid refrigerant, wherein a heat receivingsection of the liquid cooling module is disposed between said firstsemiconductor element and said mounting substrate, and a plurality ofsecondary connecting bumps provided between said package substrate andsaid mounting substrate.

In this semiconductor device, a semiconductor element is providedbetween a mounting substrate and a package substrate, so that a space isformed between the semiconductor element and the mounting substrate. Inthis space, a liquid-cooling module cooling the semiconductor element isprovided. This allows the semiconductor element to be cooled with aliquid-cooling module, and thus an allowable heating value can beincreased.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and advantages of the present invention will be moreapparent from the following description of certain preferred embodimentstaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side longitudinal sectional view showing a stacked packagewith a logic element being lowermost, a mounting substrate and a liquidcooling module in a first embodiment;

FIG. 2 is a plane view showing an arrangement of the liquid coolingmodule and a secondary connecting bump in the first embodiment;

FIG. 3 is a cross-sectional view showing an internal structure of theliquid cooling module in the first embodiment;

FIG. 4A is a perspective view showing the liquid cooling module in thefirst embodiment during the manufacturing process thereof;

FIG. 4B is a partial sectional view showing one embodiment of thestacked film of FIG. 4A;

FIG. 5 is a plane view showing the liquid cooling module in the firstembodiment during the manufacturing process thereof;

FIG. 6 is a perspective view showing a liquid cooling module in thefirst embodiment;

FIG. 7A is a side longitudinal sectional view showing a package during afirst step of the assembly process thereof in the first embodiment;

FIG. 7B is a side longitudinal sectional view showing a package during asecond step of the assembly process thereof in the first embodiment;

FIG. 7C is a side longitudinal sectional view showing a package of FIG.7B of the state in which a refrigerant flows into the liquid coolingmodule;

FIG. 8 is a sectional view showing a stacked package with a logicelement being uppermost as a comparative example;

FIG. 9 is a sectional view showing the stacked package with a logicelement being uppermost as the comparative example which is equippedwith air-cooled fins;

FIG. 10 is a graph showing an allowable heating value of the package ofthe comparative example, which is air-cooled by a fin;

FIG. 11 is a graph showing an allowable heating value of the liquidcooling package according to the present invention;

FIG. 12 is a plane view showing a first modified example of thesecondary connecting bump and the liquid cooling module in the firstembodiment;

FIG. 13 is a sectional view showing an internal structure of the liquidcooling module of FIG. 12;

FIG. 14 is a plane view showing a second modified example of thesecondary connecting bump and the liquid cooling module in the firstembodiment;

FIG. 15 is a sectional view showing an internal structure of the liquidcooling module of FIG. 14;

FIG. 16 is a plane view showing a third modified example of thesecondary connecting bump and the liquid cooling module in the firstembodiment;

FIG. 17 is a sectional view showing an internal structure of the liquidcooling module of FIG. 16;

FIG. 18 is a plane view showing a fourth modified example of thesecondary connecting bump and the liquid cooling module in the firstembodiment;

FIG. 19 is a sectional view showing an internal structure of the liquidcooling module of FIG. 18;

FIG. 20 is a plane view showing a fifth modified example of thesecondary connecting bump and the liquid cooling module in the firstembodiment;

FIG. 21 is a sectional view taken along line B-B′ of FIG. 20;

FIG. 22 is a perspective view showing the liquid cooling module of FIGS.20 and 21 during the manufacturing process thereof;

FIG. 23 is a plane view showing the liquid cooling module of FIGS. 20and 21 during the manufacturing process thereof;

FIG. 24 is a side longitudinal sectional view showing a stacked packagewith a logic element being lowermost, a mounting substrate and a liquidcooling module in a second embodiment;

FIG. 25 is a perspective view showing a recessed portion of the mountingsubstrate of FIG. 24; and

FIG. 26 is a side longitudinal sectional view showing a stacked packagewith a logic element being lowermost, a mounting substrate and a liquidcooling module in a third embodiment;

FIG. 27 is a perspective view showing the recessed portion and a hole ofthe mounting substrate of FIG. 24.

FIG. 28 is a side longitudinal sectional view showing a package during afirst step of the assembly process thereof in the third embodiment;

FIG. 29 is a side longitudinal sectional view showing a package during asecond step of the assembly process thereof in the third embodiment; and

FIG. 30 is a sectional view showing a liquid cooling module in the thirdembodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A semiconductor device of the present invention includes a packagesubstrate, a memory element stacked on its top surface side by primaryconnection, a semiconductor element primarily connected to itsundersurface side, and a secondary connecting bump surrounding thesemiconductor element. Out of secondary connecting bump rows, at leastone row extending in the outer perimeter direction from the innerperimeter is eliminated, and thereby a space that reaches thesemiconductor element from the outside of the package is provided. Aliquid cooling module and a conduit, which are separate components fromthe package, are disposed in the space. The secondary connecting bumpsare desirably disposed so as to be linearly symmetrical with respect tothe longitudinal center line or lateral center line of the packagesubstrate surface, or to the longitudinal center line and lateral centerline, or to be rotationally symmetrical with respect to the center pointof the package substrate surface. The liquid cooling module is alaminated film including a thin resin film and a thin metallic film, anda channel is formed by thermo-compression bonding. A recessed portionequal to or larger than the size of the liquid cooling module shape isdesirably formed at the mounting substrate side in the space between themounting substrate and the semiconductor element.

The invention will be now described herein with reference toillustrative embodiments. Those skilled in the art will recognize thatmany alternative embodiments can be accomplished using the teachings ofthe present invention and that the invention is not limited to theembodiments illustrated for explanatory purposes.

First Embodiment

FIG. 1 is a side longitudinal sectional view of a semiconductor devicein a first embodiment, and is a view showing the outline of itsconfiguration. A stacked package with a logic element being lowermost(LEL) designated by reference numeral 100 in FIG. 1 includes stackedmemory 12 at a top surface side of package substrate 11, and logicelement 131 at an undersurface side.

Stacked memory 12 is formed by stacking a plurality of memory elements121 in layers via primary connecting bumps 122, which are electricallyconnected to each other in the stacking direction by silicon throughelectrodes 123 formed inside memory elements 121. Memory elements 121and their electrical connection portions are protected by mold resin 14.Logic element 131 is electrically connected to package substrate 11 viaprimary connecting bumps 122, and its electrical connection portion isprotected by underfill 132. Logic element 131 and stacked memory 12 areelectrically connected with through-holes 111 in the substrate.

Stacked package with LEL 100 is electrically connected to mountingsubstrate 2 via secondary connecting bumps 15. In this configuration,the path through which the electrical signal input from secondaryconnecting bump 15 is transmitted is in the sequence of logic element131 and stacked memory 12.

Accordingly, the logic element can control distribution of signals to aplurality of memory elements 121 in advance, and therefore, signal delaycan be minimized. In the space between the bottom surface of logicelement 131 and the top surface of mounting substrate 2, heat receivingsection 31 of the thin liquid cooling module made of laminated sheets isprovided and is in close contact with them. When secondary connectingbump 15 is a solder ball, mounting height a is generally 0.5 mm orlower. Thickness h of heat receiving section 31 of the liquid coolingmodule is smaller than a due to the thickness of logic element 131.Channel height h1 of heat receiving section 31 of the liquid coolingmodule is smaller than h.

Generally, the heating value per one memory element 121 is hundreds ofmilliwatts or less. However, the heating value of logic element 131 istens of watts and large. Therefore, if heat receiving section 31 of theliquid cooling module is brought into contact with logic element 131 tocool logic element 131, the allowable heating value can be significantlyincreased as will be described later.

In this embodiment, stacked memory 12 has a configuration in which aplurality of memory elements 121 are stacked in layers. However, thememory may be a single memory. Further, stacked memory 12 may have aconfiguration in which memory elements 121 and the logic element arestacked in layers. More specifically, stacked memory 12 may have aconfiguration in which the logic element is disposed between a pluralityof memory elements 121. Further, the memory may have a configuration inwhich one or a plurality of memory elements 121 is or are disposedbetween a plurality of logic elements. Further, the member designated bynumeral 12 may be a single or a plurality of logic elements, or may be asingle or a plurality of other semiconductor elements.

Further, in this embodiment, the member designated by reference numeral100 is a stacked package with LEL, and the object to be cooled by theliquid cooling module is logic element 131. However, the object to becooled is not limited to this, and may be a memory element and anothersemiconductor element.

Here, the member designated by reference numeral 12 will be called asecond semiconductor element. Further, in this case, the memberdesignated by reference numeral 131 which is in contact with heatreceiving section 31 will be called a first semiconductor element.

The heating value of the first semiconductor element is desirably largerthan that of the second semiconductor element.

Further, the characteristics of the present invention are also includedin a semiconductor device in the case where the second semiconductorelement designated by reference numeral 12 is not present as a componentof the semiconductor device, that is to say, in the case where only thefirst semiconductor element designated by 131, which may be simplycalled a semiconductor element in this case, is electrically connectedto package substrate 11 via primary connecting bumps 122.

FIG. 2 is a view showing an example of the arrangement of the liquidcooling module and the secondary connecting bumps in this embodiment. Inthis embodiment, there are two regions between package substrate 11 andmounting substrate 2. In one region, secondary connecting bumps 15 arein the form of being sandwiched between package substrate 11 andmounting substrate 2. In the other region where secondary connectingbumps 15 are not provided, heat receiving section 31 and conduit line 32of the liquid cooling module are installed. Circle 16 shown by a dottedline shows the position of secondary connecting bump 15 which is to beprovided when conduit line 32 is not installed. In this embodiment,secondary connecting bump 15 is not provided in the position of each ofcircles 16 shown by the dotted line.

In this embodiment, heat receiving section 31 and conduit line 32 of theliquid cooling module are disposed such that they are substantiallysymmetrical with respect to the horizontal center line (parallel to thex-axis) and the longitudinal center line (parallel to the y-axis) ofpackage substrate 11. Further, since secondary connecting bumps 15 arenot provided in the positions of circles 16 shown by the dotted line,space p2 between secondary connecting bumps 15 opposite to each otheracross conduit line 32 is larger than space p1 between bumps which areactually mounted.

Thereby, conduit line 32 can be made wide, and the pressure loss of theliquid cooling module can be reduced. Secondary connecting bumps 15 aresubstantially symmetrical with the axes as described above, andtherefore, symmetry of the arrangement of a plurality of wirings insidethe semiconductor package is kept, and the lengths of a plurality ofwirings can be made substantially equal. Therefore, the resistances of aplurality of wirings can be made substantially equal, and the electricalcharacteristics of the semiconductor package can be prevented from beingimpaired.

FIG. 3 is a plane sectional view schematically showing the channel inthe liquid cooling module according to this embodiment. In FIG. 3,refrigerant 33 (i.e., liquid refrigerant) flows in from inlet port 321,passes through channel 34 inside the liquid cooling module to flow outto outlet port 322 as shown by the arrows. Channel 34 is formed to bebranched by outer wall 35 and inner wall 36 in heat receiving section 31so that the refrigerant flows in the entire area of heat receivingsection 31 while changing the flow direction.

FIGS. 4A, 4B, 5 and 6 show the heat receiving section shown in FIG. 3during the manufacturing process thereof.

FIG. 4A is a perspective view showing a laminated film constituting theliquid cooling module. FIG. 4B is a partial sectional view of thelaminated film. FIG. 5 is a plane view showing a portion to whichthermo-compression bonding is to be applied in the laminated film thatconstitutes the liquid cooling module. FIG. 6 is a perspective viewshowing a completed liquid cooling module.

When the heat receiving section is manufactured, two laminated films 38a and 38 b are superimposed on each another first as shown in FIG. 4A.Here, guide mark 383 for the channel is desirably printed in advance onat least one laminated film 38 a.

Laminated film 38 is formed by laminating heat-resistant resin films 381such as polyimide, aluminum foil 382 and the like. FIG. 4B shows asection of laminated film 38 in which aluminum foil 382 is sandwichedbetween two heat-resistant resin films 381. This allows it to have bothheat resistance and water resistance. Thickness t of the resin film isabout several micrometer to tens of micrometers.

Next, as shown in FIG. 5, thermo-compression bonding is applied alongguide mark 383 for the channel, and thereby, outer wall 35 and innerwall 36 are produced. Subsequently, unnecessary portions of laminatedfilm 38 outside outer wall 35 are cut off. FIG. 6 is a view showing astate in which a refrigerant flows through inlet port 321, channel 34and outlet port 322 of the liquid cooling module. Due to the flow of therefrigerant, inlet port 321, channel 34 and outlet port 322 areinflated. Here, the portion to which thermo-compression bonding isapplied is called a compression-bonded portion. Further, outer wall 35and inner wall 36 will be called channel walls.

FIGS. 7A, 7B and 7C are sectional views of the semiconductor device ofthis embodiment, showing the liquid cooling module and the semiconductorpackage on the mounting substrate during the steps of assembling processthereof.

First, as shown in FIG. 7A, the liquid cooling module is installed onmounting substrate 2. In FIG. 7A, only heat receiving section 31 isshown. At this time, there is no refrigerant inside the liquid coolingmodule, and therefore, channel height h0 is substantially 0 (zero).

Next, as shown in FIG. 7B, Stacked package with LEL 100 in whichsecondary connecting bumps 15 are disposed in the predeterminedpositions is placed above the liquid cooling module, and is mounted byreflow soldering at 260° C. on mounting substrate 2. Since thecomponents of the liquid cooling module are made of a material havingheat resistance such as polyimide, an aluminum foil and the like, theyhave sufficient heat resistance to the reflow temperature. Further, atthis stage, there is a gap between heat receiving section 31 and logicelement 131, and therefore, each solder, which is secondary connectingbump 15, can be mounted on each predetermined position by using aself-alignment technique.

Finally, the liquid cooling module is connected to the pump, thereservoir tank (both not shown) and the like. As shown in FIG. 7C, therefrigerant is injected into the channel of the liquid cooling module.The channel of heat receiving section 31 is inflated by injection of therefrigerant to reach height h1, and heat receiving section 31 is inclose contact with the top surface of mounting substrate 2 and theundersurface of logic element 131. This enables logic element 131 to becooled.

Here, the effect obtained by the semiconductor device of this embodimentwill be described by referring to FIGS. 8 to 11.

FIG. 8 shows a sectional view of a stacked package with a logic elementbeing uppermost (LEU) as a comparative example. In stacked package withLEU 101, logic element 131 is provided in the uppermost layer of thepackage, and the top surface of logic element 131 is exposed on thepackage top surface. FIG. 9 is a view showing a stacked package with LEU101 as the comparative example in the case where air-cooled fins 4 areprovided on the package top surface via heat conducting member 5 (e.g.,a heat conducting sheet or grease) as an ordinary cooling means. In thiscase, cooling is performed by passing air into gaps between fins 4.

Next, the example is shown, in which forced-convection cooling isperformed by providing the air-cooled fins having the samespecifications in the case of a stacked package with LEL 100 and LEU101, and the allowable heating values thereof are evaluated.

FIG. 10 is a graph showing the allowable heating values of the stackedpackage with LEU and LEL when the air-cooled fins are provided andthermal hydraulic analysis is performed by varying the wind velocity asa parameter. FIG. 10 shows that the allowable heating value of 10 to 20W is obtained by providing the air-cooled fins in the stacked packagewith LEU, whereas in the stacked package with LEL, 2 W is the limit evenwhen the wind velocity is increased. This is caused by the heatresistance becoming large because the package substrate, memory elementand the like are interposed in the heat radiation path between thelowermost logic element and the air-cooled fins. Specifically, it isclear that reduction in the heat resistance from the logic element tothe heat radiator is important for increasing the allowable heatingvalue of the logic element.

FIG. 11 is a graph showing the allowable heating value of the stackedpackage with LEL shown in FIG. 1 when the thin liquid cooling module isbrought into close contact with the undersurface thereof, and whenthermal hydraulic analysis is performed by varying the kinds of therefrigerants and the flow rate as parameters. As the refrigerant, wateror an anti-freezing solution is used.

FIG. 11 shows that the allowable heating value is 20 W or more even inthe case of the refrigerant flow rate of 10 ml/min, and that theallowable heating value reaches 50 to 70 W when the refrigerant flowrate is 100 ml/min.

The heat radiating ability is larger in water than in an anti-freezingsolution However, since water is likely to corrode the component such asa pump, the refrigerant is desirably an anti-freezing solution. Even theanti-freezing solution enables the allowable heating value of 50 W whenthe flow rate is 100 ml/min. In this way, the thin liquid cooling moduleallows the allowable heating value of the stacked package with LEL to bedrastically increased.

FIG. 12 shows another example of the arrangement of the liquid coolingmodule and the secondary connecting bumps of this embodiment. Secondaryconnecting bumps 15 are arranged so as to be rotationally symmetricalwith respect to the axis perpendicular to the paper surface through thepackage center point A. Conduit line 32 is disposed in the region ofcircles 16 shown by the dotted line, where secondary connecting bumps 15are not provided. Since secondary connecting bumps 15 shown in FIG. 12have a rotationally symmetrical arrangement, there is no possibility ofdeterioration of the electrical characteristics of the semiconductorpackage.

FIG. 13 is a sectional view showing an internal structure of the liquidcooling module of FIG. 12. The channel shape of FIG. 13 is a zigzag inwhich the flow direction of the refrigerant is reversed four times.However, the channel shape is not limited to this shape as long as thechannel is formed continuously from inlet port 321 to outlet port 322without interruption. In this embodiment, refrigerant 33 flows in frominlet port 321 at the lower left side, and flows out to outlet port 322at the upper right side.

FIG. 14 is a view showing another example of the arrangement of theliquid cooling module and the secondary connecting bumps of thisembodiment. Secondary connecting bumps 15 are arranged so as to bemirror symmetrical with respect to the longitudinal line parallel to they-axis passing through the package center point A. Conduit line 32 isdisposed in the region of circles 16 shown by the dotted line, wheresecondary connecting bumps 15 are not provided. Since secondaryconnecting bumps 15 shown in FIG. 14 have a mirror symmetricalarrangement, there is no possibility of deterioration of the electriccharacteristics of the semiconductor package.

FIG. 15 is a sectional view showing an internal structure of the liquidcooling module of FIG. 14. The channel shape of FIG. 15 is a zigzag inwhich the flow direction of the refrigerant is reversed five times.However, the channel shape is not limited to this shape as long as thechannel is formed continuously from inlet port 321 to outlet port 322without interruption.

FIG. 16 is a view showing another example of the arrangement of theliquid cooling module and the secondary connecting bump of thisembodiment. Secondary connecting bumps 15 are not symmetrical withrespect to the longitudinal and horizontal lines (parallel to the y- andx-axes) passing through the package center point A. Conduit line 32 isdisposed in the region of circles 16 shown by the dotted line, wheresecondary connecting bumps 15 are not provided. Secondary connectingbumps 15 shown in FIG. 16 have no symmetrical arrangement. However, whenpriority is given to disposing the liquid cooling module, such anarrangement can be adopted.

FIG. 17 is a sectional view showing an internal structure of the liquidcooling module of FIG. 16. In this case, inlet port 321 and outlet port322 are separated by a wall to be disposed adjacent to each other. Thechannel shape of FIG. 17 is a zigzag in which refrigerant 33, whichflows into heat receiving section 31 from inlet port 321, turns overfive times after reaching the opposite side of inlet port 321 and afterturning 90°. However, the channel shape is not limited to this shape aslong as the channel is formed continuously from inlet port 321 to outletport 322 without interruption.

FIG. 18 is a view showing another example of the arrangement of theliquid cooling module and the secondary connecting bump of thisembodiment. Secondary connecting bumps 15 are arranged so as to bemirror symmetrical with respect to the horizontal line parallel to thex-axis passing through the package center point A. Conduit line 32 isdisposed in the area of circles 16 shown by the dotted line, wheresecondary connecting bumps 15 are not provided. Secondary connectingbumps 15 shown in FIG. 18 have a mirror symmetrical arrangement, andthus there is no possibility of deterioration of the electriccharacteristics of the semiconductor package. Arrangement of secondaryconnecting bumps 15 is not limited to that of FIG. 18, and may be anarrangement in which the mirror symmetry with respect to thelongitudinal center line parallel to the y-axis is kept.

FIG. 19 is a sectional view showing an internal structure of the liquidcooling module of FIG. 18. The channel shape of FIG. 19 is a zigzag inwhich the flow of refrigerant 33, which flows into heat receivingsection 31 from inlet port 321, is turned five times in a half region ofheat receiving section 31 and further turned five times in the otherhalf region thereof to flow out to outlet port 322. The channel shape isnot limited to this shape as long as the channel is formed continuouslyfrom inlet port 321 to outlet port 322 without interruption.

FIG. 20 is a sectional view showing an internal structure of anotherexample of the configuration of the liquid cooling module. FIG. 21 is asectional view taken along line B-B′ of FIG. 20.

In this configuration, the channel is three-dimensional. As shown inFIG. 20, refrigerant 33 flows into heat receiving section 31 from inletport 321, and passes through a plurality of flow paths which are formedsuch that the flow path nearer to the horizontal center line (parallelto the x-axis) has a narrower width. Thereafter, the flow of refrigerant33 is turned at the opposite side of inlet port 321 to flow out throughoutlet port 322. Since the difference in distance between inner walls 36causes a difference in distribution of the channel resistance,refrigerant 33 that flows into heat receiving section 31 from the regionnear the horizontal center line can be distributed to all of the flowpaths. More specifically, the flow path width, which is the distancebetween inner walls 36, near the horizontal center line becomes narrow,and the flow path width far from the horizontal center line becomeswide. Thereby, the flow rate in the flow path near the horizontal centerline is limited, and the flow rate in the flow path far from thehorizontal center line is ensured. As a result, the flow velocities inthe respective flow paths become substantially equal, so that the heatflux (i.e., heat flow rate per unit area) of heat receiving section 31is made substantially uniform independent of the flow path.

As shown in FIG. 21, the horizontal length of the inner wall formed bylaminated film 38 c is shorter than those of laminated films 38 a and 38b, and thereby, a flow path for turning the flow of refrigerant 33 isensured. The configuration of the distance between inner walls 36 is notlimited to that in this channel shape. Further, while the flow rate(i.e., flow velocity) of each flow path is regulated (i.e., madesubstantially equal) by changing the distance between inner walls 36(i.e., flow path width) in the channel before turning the flow as shownin FIG. 20, the flow path widths in the channel after turning the flowcan be made substantially equal to each other. More specifically, thestructure may be adopted, in which the configuration of the distancebetween inner walls 36 (i.e., flow path width) is changed before andafter turning the flow.

FIGS. 22 and 23 show an example of a three-dimensional channel duringthe manufacturing process thereof. As shown in FIG. 22, three laminatedfilms 38 a, 38 b and 38 c are superimposed on one another. Among them,the laminated film designated by 38 c to be the inner wall has cutportion 385 at the right-hand side of FIG. 22, so that it is shorterthan the other two films. As shown in FIG. 23, after three films aresuperimposed on one another, outer wall 35 and inner wall 36 of thechannel are formed by thermo-compression bonding along guide mark 383.Here, an example is shown in which films that are cut into the shape ofthe liquid cooling module are used. However, as shown in FIGS. 4 to 6,after thermo-compression bonding by using sheets that are larger thanthe size of the liquid cooling module, unnecessary portions may be cutoff.

Second Embodiment

FIG. 24 shows a side sectional view of a semiconductor device in asecond embodiment. The configuration of a stacked package with LEL 100is the same as that of the first embodiment. However, in thisembodiment, recessed portion 21 is provided in mounting substrate 2, andthereby, channel height h2 of the liquid cooling module is increased.For example, if recessed portion 21 of 0.5 mm is provided in themounting substrate of 1.27 mm, the channel height which is about twiceas high as that of the first embodiment can be ensured, and the pressureloss of the channel of heat receiving section 31 can be reduced.

FIG. 25 is a perspective view showing the liquid cooling module and themounting substrate of this embodiment. As shown in FIG. 25, recessedportion 21 of the mounting substrate is formed into a size which is anoutside dimension of heat receiving section 31 and conduit line 32, orlarger. By providing recessed portion 21 in the mounting substrate,positioning when mounting the liquid cooling module is facilitated.

Third Embodiment

FIG. 26 shows a side sectional view of a semiconductor device in a thirdembodiment. The configuration of a stacked package with LEL 100 is thesame as those of the first and second embodiments. In this embodiment,as in the second embodiment, recessed portion 21 for increasing channelheight h2 of heat receiving section 31 and hole 22 (i.e., athrough-hole) for receiving conduit line 32 are provided in mountingsubstrate 2. By passing conduit line 32 through mounting substrate 2, ascompared with the second embodiment, the channel sectional area ofconduit line 32 is increased and the pressure loss can be reduced.Further, there is no need to dispose conduit line 32 between packagesubstrate 11 and mounting substrate 2, and therefore, as compared withthe first and second embodiments, the number of secondary connectingbumps 15, that is, the number of input and output terminals, which areto be disposed therebetween, can be increased.

FIG. 27 is a perspective view showing the liquid cooling module and themounting substrate of this embodiment. As shown in FIG. 27, recessedportion 21 of mounting substrate 2 is formed into a size which is anoutside dimension of heat receiving section 31 and conduit line 32, orlarger. Further, hole 22 slightly larger than conduit line 32 isprovided at recessed portion 21.

FIGS. 28 to 30 are views showing the liquid cooling module of thisembodiment during the steps of the assembly process thereof. FIG. 28 isa side longitudinal sectional view showing the liquid cooling module ofthis embodiment during a first step in the assembly process thereof.FIG. 29 is a side longitudinal sectional view showing the liquid coolingmodule of this embodiment during a second step of the assembly processthereof. FIG. 30 is a sectional view showing the liquid cooling moduleof this embodiment.

First, as shown in FIG. 28, cylindrical conduit line 32 provided withflange 323 is inserted into hole 384 formed in laminated film 38 b.

Next, as shown in FIG. 29, after thermo-compression bonding flange 323of conduit line 32 to laminated film 38 b, laminated film 38 a issuperimposed thereon.

Finally, as shown in FIG. 30, part of laminated films 38 a and 38 b arebonded to each other by thermo-compression bonding. As a result, outerwall 35 and inner wall 36, and thereby channel 34 are formed.Refrigerant 33 flows in from inlet port 321 and out to outlet port 322.

According to the present invention, the following effect is obtained.

A signal to the stacked memory can be transmitted over the shortest paththrough the logic element, so that high speed communication is enabled.

Further, the liquid cooling module allows the logic element to becooled, so that the allowable heating value can be increased.

Further, the liquid cooling module can be made so thin as to be placedin a narrow space between the logic element and the mounting substrate.

Further, the conduit line from the outside of the semiconductor deviceto the liquid cooling module can be ensured.

Further, the secondary connecting bumps can have line symmetrical orrotationally symmetrical arrangements, so that there is no possibilitythat the electrical characteristics will deteriorate.

Further, the liquid cooling module is a separate component from thesemiconductor device, in other words, the channel can separate from thewiring circuit surface of the logic element. Therefore, there is nopossibility that the wiring circuit surface and the electricalconnection portions will deteriorate due to corrosion.

Further, the liquid cooling module is composed of the laminated film inwhich the metal foil is sandwiched between the heat-resistant thin resinfilms. Therefore, the liquid cooling module has solder reflow resistanceand high water resistance. Further, the liquid cooling module can beinstalled before the package is mounted and can be prevented fromcausing leakage of the refrigerant liquid.

Further, positioning for mounting of the liquid cooling module isfacilitated in cases where the recessed portion, that corresponds to theliquid cooling module in the mounting substrate, is provided.

Further, an increase in the channel sectional area of the conduit lineis facilitated in cases where the hole for receiving the conduit line inthe mounting substrate is provided, so that the pressure loss can bereduced. Further, there is no need to dispose the conduit line betweenthe package substrate and the mounting substrate, and therefore, thenumber of input and output terminals disposed therebetween can beincreased.

It is apparent that the present invention is not limited to the aboveembodiments, but may be modified and changed without departing from thescope and spirit of the invention.

1. A semiconductor device, comprising: a mounting substrate; asemiconductor element provided above said mounting substrate; a packagesubstrate provided above said mounting substrate with said semiconductorelement therebetween, and electrically connected to said semiconductorelement via a primary connecting bump; a liquid cooling module coolingsaid semiconductor element by a liquid refrigerant, wherein a heatreceiving section of said liquid cooling module is disposed between saidsemiconductor element and said mounting substrate; and a plurality ofsecondary connecting bumps provided between said package substrate andsaid mounting substrate.
 2. The semiconductor device according to claim1, wherein the heat receiving section of said liquid cooling module isin close contact with said semiconductor element.
 3. The semiconductordevice according to claim 1, wherein a conduit line of said liquidcooling module is received between said package substrate and saidmounting substrate.
 4. The semiconductor device according to claim 1,wherein two regions are formed between said package substrate and saidmounting substrate, in one of which said conduit line of said liquidcooling module is received, in the other of which said secondaryconnecting bumps are provided.
 5. The semiconductor device according toclaim 1, wherein said secondary connecting bumps are disposed so as tobe substantially line symmetrical with respect to at least one linepassing through a center point of a surface of said package substrate,or to be substantially rotationally symmetrical with respect to an axispassing through the center point and being normal to the surface of saidpackage substrate, said surface contacting said secondary connectingbumps.
 6. The semiconductor device according to claim 1, wherein theconduit line of said liquid cooling module is received in a through-holeprovided in said mounting substrate.
 7. The semiconductor deviceaccording to claim 1, wherein a thickness of the heat receiving sectionof said liquid cooling module is smaller than a mounting height of saidsecondary connecting bumps.
 8. The semiconductor device according toclaim 1, wherein said liquid cooling module is composed of a laminatedfilm in which both surfaces of a metal foil are sandwiched between thinresin films, and wherein a channel wall of said liquid cooling module isformed by compression-bonded portions of said two laminated films whichare superimposed on each other.
 9. The semiconductor device according toclaim 1, wherein the heat receiving section of said liquid coolingmodule is disposed between a recessed portion provided in said mountingsubstrate and said semiconductor element.
 10. A semiconductor device,comprising: a mounting substrate; a first semiconductor element providedabove said mounting substrate; a package substrate provided above saidmounting substrate with said first semiconductor element therebetween,and electrically connected to said first semiconductor element via aprimary connecting bump; a second semiconductor element provided abovesaid first semiconductor element with said package substratetherebetween, and electrically connected to said first semiconductorelement via said primary connecting bump and a through electrodeprovided at said package substrate; a liquid cooling module cooling saidsemiconductor element by a liquid refrigerant, wherein a heat receivingsection of the liquid cooling module is disposed between said firstsemiconductor element and said mounting substrate; and a plurality ofsecondary connecting bumps provided between said package substrate andsaid mounting substrate.
 11. The semiconductor device according to claim10, wherein the heat receiving section of said liquid cooling module isin close contact with said first semiconductor element:
 12. Thesemiconductor device according to claim 10, wherein a conduit line ofsaid liquid cooling module is received between said package substrateand said mounting substrate.
 13. The semiconductor device according toclaim 10, wherein two regions are formed between said package substrateand said mounting substrate, in one of which said conduit line of saidliquid cooling module is received, in the other of which said secondaryconnecting bumps are provided.
 14. The semiconductor device according toclaim 10, said secondary connecting bumps are disposed so as to besubstantially line symmetrical with respect to at least one line passingthrough a center point of a surface of said package substrate, or to besubstantially rotationally symmetrical with respect to an axis passingthrough the center point and being normal to the surface of said packagesubstrate, said surface contacting said secondary connecting bumps. 15.The semiconductor device according to claim 10, wherein a conduit lineof said liquid cooling module is received in a through-hole provided insaid mounting substrate.
 16. The semiconductor device according to claim10, wherein a heating value of said first semiconductor element islarger than a heating value of said second semiconductor element. 17.The semiconductor device according to claim 10, wherein a thickness ofthe heat receiving section of said liquid cooling module is smaller thana mounting height of said secondary connecting bumps.
 18. Thesemiconductor device according to claim 10, wherein said liquid coolingmodule is composed of a laminated film in which both surfaces of a metalfoil are sandwiched between thin resin films, and wherein a channel wallof said liquid cooling module is formed by compression-bonded portionsof said two laminated films which are superimposed on each other. 19.The semiconductor device according to claim 10, wherein the heatreceiving section of said liquid cooling module is disposed between arecessed portion provided in said mounting substrate and said logicelement.
 20. A liquid cooling module, comprising: a heat receivingsection and a conduit line formed by laminated films superimposed oneach other, in each of said laminated films a metal foil is sandwichedbetween thin resin films, said heat receiving section and conduit lineincluding a channel through which a liquid refrigerant flows; andwherein a channel wall of said channel is formed by compression-bondedportions of said two or three laminated films which are superimposed onone another.